Re: Mid lactation milk feverMilk Fever is a direct result of ration imbalances. Calcium and magnesium are either not high a enough or tied up because your Phos and Iron levels are really high and out of balance with your other minerals. Some ways this can happen is by feeding to much canola or distillers grains because they have very high levels of Phos. and Iron. Your Calcium should be in a 2 to 1 ratio with Phos. and a 1 to 1 ratio with pot-ash.

Re: Mid lactation milk feverOne thing to consider is the bioavailability of the minerals in the forage and the ones used to balance the diet.
I would suggest wet chemistry on the minerals then use sources that are more available. Or raise the levels of calcium and mag. I would be curious to know the potassium level in the forages and total diet.
I also would suspect toxins or possibly higher fat levels that could be tying upsome of the calcium in the diet.